Colour map optimisation example in a broken state?

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [X] For Python issues, I have tested with the [latest development wheel](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### My Question

It appears that the color map optimisation example (now called `color_map_optimization_for_reconstruction_system.py`?) no longer has clear instructions on how to run it, or the input it expects.

It seems it once loaded the fountain dataset, and the old version of the docs link to this. Now it consumes a config file, but it's unclear what exactly should be in this config file.

Could someone please advise?